A test for comparing the means of two samples, or the mean of one sample (or even parameter estimates) with a specified value; also known as the "Student t-test" after the pseudonym of its inventor.

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6 views

Do Cohen's d and Hedges' g apply to the Welch t-test?

How do you go about calculating effect size for the Welch t-test?
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139 views

Does Bonferroni apply to both parametric and non-parametric data?

I have run 6 independent-samples t-tests, and 4 Mann Whitney U tests. When applying bonferroni correction, does it apply across all 10 tests? My hypotheses are that there will be 4 significant ...
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9 views

Statistical test to determine if system A or B captures a trend more accurately

I have a known variable, for example a trend of heart rate, and two systems (A, & B) who sample this variable the same number of times but at different, unequal intervals. What are some suitable ...
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6 views

one sample t test for clustered data in R

How shall I do one sample t test for clustered data? For instance, I have N = 100 number of observations, which are obtained from 5 different regions. I'd like to test whether the outcome y is ...
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17 views

There are many statistical erros in this results and discussion. Can someone help me locate them? [on hold]

Results: Data Coding and Exploratory Data Analysis All data were entered into a single SPSS data file for analysis. Seven variables were coded: 1. Sex 2. Total amount of television viewing hours ...
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2answers
59 views

Why is the degrees of freedom for a matched pairs $t$-test the number of pairs minus 1?

I am used to knowing "degrees of freedom" as $n - r$, where you have the linear model $$\mathbf{y} = \mathbf{X}\boldsymbol{\beta} + \boldsymbol{\epsilon}$$ with $\mathbf{y} \in \mathbb{R}^n$, ...
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3 views

Post-hoc for independent t-tests for a total scale score and subscale scores

I'm comparing two groups on scores on the Dissociative Experiences Scale, and its subscales, using independent-samples t-tests. The DES is a 28 item questionnaire yielding a total DES score. There are ...
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7 views

The use of MANOVA, ANOVA or t-tests for Likert-style data

I have two groups I would like to compare on a series of Likert-style mood dimensions (e.g. Very Sad - Slightly Sad - Neutral - Slightly Happy - Very Happy). The sample sizes are 19 and 63. The data ...
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14 views

Why statistical test always show evidence whether or not EMH holds? [on hold]

This is the question in my assignment. I don't understand what its asking about?
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15 views

Independent t tests and unequal same size

Just wondering if when 'Equal variances are assumed', but the number of participants in the experiment are unequal (and the sample sizes are $<30, n_1=24$ and $n_2=25$) is it still okay to continue ...
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10 views

Testing 2 populations and how the effect of one variable impacts the score of a 2nd variable

Brief summary of my study: I am studying two types of organizations, A and B. For both organizations A and B, I measured how centralization affected innovation. There were significant differences ...
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21 views

Paired independent sample t-test?

I have two methods of processing certain data, where one is a more advanced version of the other. After processing the data, the output is scored from -1 to 1. I have a set of 7 distinct data points ...
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15 views

Calculating Tukey HSD for a subset of comparisons - can I do this?

A colleague has about 50 samples, each with 2 conditions (treated and non-treated). The data is continuous and normal, and there are 3 data points in each sample-treatment combination. They'd like to ...
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1answer
16 views

Advice on method for correlation and regression of data

I'm having a dataset where I've measured the decay of a certain drug at different time intervals. I have on measurement for each time interval, and I want to test if there is a correlation. Straight ...
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1answer
22 views

Data violates homogeneity of variances and is not normally distributed. Can I still run the t-test?

I have two categorical, independent groups, and a continuous dependent variable. The data violates homogeneity of variances, and the dependent variable is not normally distributed for each of the two ...
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1answer
60 views

Statistic on non-normalized data

Not that strong in statistics, so I need a little help getting started with some data I've gathered. In my experiment subjects had to perform tasks while I took time for them to complete it. Now, I ...
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25 views

Which normality? [closed]

One of the assumption of t-test is normality. Which I want to check using the kurtosis and skewness on spss. But do we check normality for the dependant variable or for each group on the dependant ...
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5 views

Unsure of how to test a mixture model coefficient and standard error.

This is my first question on Stack Exchange so please excuse any faux pas! I've been working with a mixture model from the paper "Efficient estimation for an accelerated failure time model with a ...
1
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1answer
19 views

Weighted, Paired-Sample T-test? in R [closed]

In R you can run a paired t-test (e.g. t.test(x, y, paired=TRUE)) as well as a weighted t-test (e.g. ...
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16 views

Compare two values for same measurement between two groups

I have a set of data, that I need to compare. Set consists of two measurements from same individual (right and left arm and legs for example)k like below: ' values_1right - 1, 4, 5, 7; values_1left ...
3
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1answer
68 views

Kolmogorov–Smirnov test vs. t-test

I'm having some difficulty in understanding the interpretation of the 2 sample KS test, and how it is different from a regular t test between 2 groups. Lets say I have males and females doing some ...
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20 views

Derive a t-test for $\beta_1$ [closed]

I'm having a bit of an issue trying to figure out how to derive a $t$-test for this question. I know I probably need to construct a likelihood function but I'm a bit confused about how to do that. ...
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22 views

Confused about F-contrast and F-test in statistical software

Let's say I have an estimated parameter $\beta$ from a general linear model for 2 subject groups (with the $\beta$s corresponding to their means). If I wanted to do a two sample t test in a ...
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1answer
17 views

Multivariate Regression vs T-test: and implication for multiple comparisons

I have a data frame with different outcome measures (DV1:4) for participants some partcipant with additional IVs 1:2. ...
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10 views

Paired samples t-test (within-subjects) shows significant effect, BUT no main effect shows in Mised ANOVA - help!

Running some data looking at pseudoneglect: participants viewed figures that either had no change or small change in either left or right visual fields. t-test gave a signficant result, with ...
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5 views

Significance Test in Filtering

I have N worker scores, which are the results of how well they did on a single task, and a criteria that dynamically filters (ie. removes) some of the workers from this dataset. On average, roughly ...
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12 views

Comparing Self-Report Data to Binary results

I have two sets of data: DES scores (self-report) and whether dissociation was experienced during an experiment (yes or no). My sample size is 83 (71 no, 12 yes). I want to know if high DES scores are ...
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44 views

Z score or not?

I have a test divided into two sections of 25 questions each. The two sections (A & B) use different likert scales: A - 0 to 6, and B - 1 to 5. I want to calculate the mean score (score / number ...
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1answer
22 views

Interpreting t-test results : Need a sanity check regarding t-statistic sign

Rookie stat question here, hoping to get a sanity check... So lets say that I have two groups, A and B. I run a two tailed t test in R, t.test(A, B, var.equal = TRUE). If my t-statistic value ...
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1answer
16 views

Test for significance of peaks (maximum) in time series

I have a time series of values, something like this: ...
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2answers
30 views

Using t-test/ANOVA on bounded data

Can a t-test/ANOVA approach to hypothesis testing be carried out when data has well-defined upper and lower limits and is not continuous? Let's assume a situation where data are generated by some ...
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0answers
18 views

Comparing binomial outcomes from prediction algorithms in R

I've written a simple model to predict the outcome of soccer games based on some input. The outcome is either "H","D",or "A", short for home team, away team, or draw. I'm comparing the results of this ...
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31 views

Outlier transformation or no transformation?

I have two group's of 25 people each. I want to know if there a difference between them on a past experience of happiness . I have a test with 100 question in it and all question have an a and b ...
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1answer
49 views

Two t test or factorial anova?

I have two groups of maybe 25 people each. I want to know if there a difference between the two on a happiness score depending if the from one group or another (A or B) and if they'r old or yougn (C ...
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20 views

How to apply Chi Squared test according to this Simulation?

I would like to introduce the following scenario to better clarify my question: Let's say that one day while doing research on the city of Villy God has appeared to me and told me that city there are ...
0
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1answer
15 views

Comparing mean difference between groups where raw data follows a long tail distribution

I am trying to determine if there is a mean difference between two test groups. The raw data (continuous scores) is distributed according to a long tail distribution. Each test group has more than ...
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17 views

Is specific data point significantly different than simulated distribution?

I have performed a simulation 1000 times that has given me a distribution that looks like so: I would now like to determine if a specific value (x = 140) is significantly different than the ...
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2answers
20 views

Comparing the means of 6 groups, binary dependent variable

I accomplished a field experiment which results in six differently treated groups (including one control group, each n = 300). Due to randomization all groups are expected to be equal in terms of ...
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0answers
29 views

Hypothesis testing: t-test and p-value conflict

I am doing a one-tailed hypothesis test on the exper coefficient. My null is the coefficient is not different from zero and my alternative is that the coefficient is greater than 0. I'm using a 5% ...
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1answer
30 views

Interpreting T Test results from R t.test()

Background on what I am doing... I have 31 years of Landsat satellite data, and have extracted spectral reluctance and calculated 13 unique spectral based vegetation metrics for a series of 16 field ...
2
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1answer
34 views

T-test or two-way mixed ANOVA?

I have a two-group pre-test/post-test design with one dependent variable. I want to find out whether or not an intervention has been effective. Would it be more appropriate to do a t-test on the gain ...
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8 views

Ranking data sets by means etc. (unequal sample size and variance)

I want to rank several lists of data by their tendency to be larger or their capacity to be larger when extrapolated. Is there a way to do this effectively?
5
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1answer
112 views

Can a paired t-test test if the difference between two means is less than a specific value?

In paired t-tests we test if the difference in means if 0 (or another value). I'm wondering if it's possible to instead test if the difference is less than x?
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2answers
50 views

t Test, Chi Squared or logistic regression..?

20 subjects Day 1. Shooting test - Basketball free throw shooting accuracy (number of successful shots out of 10) Day 2. Given coaching and can practice technique. Day 3. Shooting test again (as ...
1
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1answer
38 views

2x2 experimental design: t-tests vs. mixed anova analysis

I have conducted an experimental study, with 1 within-variable (time: T1 and T2) and 1 between-variable (group: control and treatment), measuring just one dependent variable. I understand that this ...
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0answers
7 views

How to infer a relationship between a categorical variable with 2 categories, and a discrete, interval level quantitative variable?

I am looking to use SPSS statistics / graphs to infer a relationship between a categorical variable with two categories, and a quantitative variable (income) with defined parameters (meaning it is not ...
1
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2answers
22 views

Comparing mean test scores (different tests, same group)

I have the following problem: There is 1 group of students (student 1, student 2, ..., student n) This group of students takes several tests (math, French, Biology) - all scored as percentages ...
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2answers
96 views

What statistical test would I use to show there is no difference in runtime between algorithms on different datasets?

I have two algorithms, and each of them was run on many different data sets. It looks like this (this is dummy data): ...
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28 views

t.test and permutation test results providing totally divergent answers

I have a data set with two classes and completely unbalanced samples sizes between the two classes. Note that even though I am showing some R code here, this is not a programming question. ...